太白山北坡成土因素及不同土壤垂直带谱的比较

在系统地考察太白山北坡地质、地貌、气候和植被等成土因素的基础上,总结和回顾了用土壤发生分类和土壤系统分类两种分类体系划定的太白山北坡土壤垂直带谱。根据最新的土壤系统分类,太白山北坡的土壤垂直带谱是:暗瘠寒冻雏形土(3500～3767m)———暗沃寒冻雏形土(3300～3500m)———酸性湿润雏形土(2500～3300m)———简育湿润淋溶土(1400～2500m)———简育干润淋溶土(<1400m)。分析、比较表明:两种体系有密切联系,均以成土因素为依据,建立在土壤发生学理论之上;与土壤地理发生分类相比,土壤系统分类用可以度量的诊断层和诊断特性进行土壤分类,不仅能够反映出山地土壤成土因素的垂直变化趋势,而且避免了太白山北坡土壤类型鉴定上的许多歧义。

Soil formation factors and comparison among different altitudinal zonations of the soils on northern slope of the Taibai Mountains

The altitudinal zonation of natural landscape have distinct characteristics on the northern slope of the grand Taibai Mountains. The landforms consist of the higher district of the mountain all over which glaciers remain scattered, the middle district characterized by stone forest, and the lower district covered with loess. The mountain climate may be divided into four zonations: subfrigid zonation→frigid-temperate zonation→temperate zonation →warm-temperate zonation. The altitudinal vegetation zonations are : zonation of alpine shrubby meadow →alpine conifer zonation →birch zonation →zonation of mixed Form. plnus armandi, Quercus and deciduous broad-leaved forests →low mountain and hill dry deciduous broad-leaved forests and oriental arborvitae zonation. Influenced by those factors, the representative altitudinal zonations of the soils have been formed on the northern slope of the Taibai Mountains. But when pedogenetic classification was applied, there were many different classification results of the soil altitudinal zonations on the northern slope of the Taibai Mountains. Because the pedogenentic classification was based on the biologic and climatic conditions, and the soil forming processes, the central conceptions were emphasized but the boundaries of the conceptions were neglected in the pedogenetic classification. For convenience of international communication, the Chinese Soil Taxonomy was published in 1995. Then the characterizations and the factors of soil formation were investigated on the northern slope. According to the Chinese Soil Taxonomy (revised proposal), the result of the soil Taxonomy is obtained:Umb-Cryic Cambisols (>3 500m) →Mol-Cryic Cambisols (3 300～3 500m) →Acid-Udic Cambisols(2 500～3 300m) →Hap-Udic Luvisols (1 400～2 500m) →Hap-Ustic Luvisols (<1 400m). The result of the Taxonomy coincides basically with that of the pedogenetic classification and the boundaries roundly identify with each other. The results of two soil classification systems show that the Chinese pedogenetic classification is based on the pedogenic theory, and the Chinese Soil Taxonomy is guided by soil genesis principle. There are close relations between two classification systems. In addition, measurable diagnostic horizon and diagnostic characteristics are used to classify soils in the Chinese Soil Taxonomy, which make soil classification more quantitative and more objective, and soil classification standardized.